OBJECTIVES : Patients with type 2 diabetes mellitus (T2DM) are at higher risk of comorbid depression and anxiety. Consequently, they are prescribed antidepressant for symptom amelioration. The objective was to assess the impact of disease severity (defined according to antidepressant utilization) on clinical outcomes of T2DM.

METHODS : A retrospective cohort was conducted utilizing electronic medical record (EMR) data from a primary care physician group in western Pennsylvania. Patients with at least 12 months of EMR data post-diagnosis of T2DM (ICD-9 CM 250.00, 250.02) were identified. The presence of comorbid depression and/or anxiety was identified by ICD-9 CM coding. The daily dose of antidepressant (based on the drug monograph) was utilized as a surrogate measure for disease severity, stratifying patients into ‘mild/moderate’ (below the maximum recommended dose) and ‘severe’ (at the maximum dose) categories. Descriptive analyses were conducted to assess the change in clinical outcomes (HgA1c, blood glucose [BG], blood pressure [BP], cholesterol [LDL/total] and weight) over a longitudinal time period between groups using repeated measures ANOVA.

RESULTS : Of 1822 adults with T2DM, 184 (10.1%) had comorbid diagnoses of depression or anxiety as well as documented treatment with an antidepressant. Based on dose, a total of 152 were classified as ‘mild/moderate’ and 32 as ‘severe.’ Both groups were predominantly female (64.5-71.9%) and Caucasian (61.2-75%) with mean age of approximately 59 years. No significant difference was found among demographic factors between groups. Over the time period studied, HgA1c, LDL, total cholesterol and weight were reduced significantly in the ‘mild/moderate’ group, while weight was the only outcome that significantly decreased in ‘severe’ patients (Δ = -2.49 kg, p=0.017). Between groups differences did not detect any significant difference between ‘mild/moderate’ and ‘severe’ patients(p=0.438)

CONCLUSIONS : This study was limited by sample size, but the findings suggest that severity of depression/anxiety has limited influence upon clinical outcomes in patients with T2DM.